Which ascending tract carries fine touch, vibration, and proprioception?

• A. Spinothalamic tract
• B. Dorsal columns
• C. Corticospinal tract
• D. Reticulospinal tract

Answer: (B)

Fine touch, vibration, and proprioception are carried by the dorsal column–medial lemniscus pathway. These discriminative somatosensory signals travel up the spinal cord in the dorsal columns, with the lower body sending fibers through the gracile fasciculus and the upper body through the cuneate fasciculus. They rise ipsilaterally to the medulla, synapse in the gracile and cuneate nuclei, cross there via the internal arcuate fibers, and then ascend as the medial lemniscus to the thalamus and on to the somatosensory cortex. This pathway provides precise, well-localized touch and awareness of body position and vibration. Other major tracts serve different roles: the spinothalamic tract relays crude touch, pain, and temperature; the corticospinal tract carries motor commands; the reticulospinal tract influences posture and reflexes. So for fine touch, vibration, and proprioception, the dorsal columns are the correct pathway.